1. Field of the Invention
The present invention relates to electric push bar technology, and more particularly to an electric push bar assembly having a release mechanism coupled between a retractable tube and a connector and operable for enabling a retractable tube thereof to be retracted manually when power failed or when the electric push bar assembly is damaged.
2. Description of the Related Art
Various types of electric push bars with different mechanical designs and transmission mechanisms are widely used in electric beds, electric massage chairs, lifters, exercisers and fitness machines. These electric push bars commonly use a motor drive to rotate a transmission mechanism, causing a retractable tube to extend out or to retract for elevation adjustment. In case of emergency, a user can operate an internal clutch device of the electric push bar to release the retractable tube from the load, allowing the load to be lowered rapidly. However, when the retractable tube is released with the internal clutch device from the load, the load will fall suddenly, causing an impact or accidental damage or personal injury.
FIG. 12 illustrates an electric push bar assembly according to the prior art. According to this prior art design, the electric push bar assembly comprises an electric push bar D, and a release mechanism. The electric push bar D comprises a retractable tube D1, a transmission screw (not shown) rotatable by a power drive through a gear set to cause linear movement of the retractable tube D1, and a connector D2 connected to the load (for example, electric bed or electric massage chair). The release mechanism comprises a first socket A connected to the retractable tube D1 of the electric push bar D, a second socket B connected to the connector D2 and movably coupled to the first socket A, and a clutch module C formed of a barrel C1, a first clutch ring plate C2 and a second clutch ring plate C3 mounted on the barrel C1. If the second clutch ring plate C3 is not released, two internal engagement teeth C11 of the barrel C1 are respectively engaged with two locating grooves D11 of the retractable tube D1. At this time, the connector D2 is movable with the retractable tube D1 for elevation or angular position adjustment.
When the clutch module C is released, the internal engagement teeth C11 of the barrel C1 are disengaged from the respective locating grooves D11 of the retractable tube D1. Thus, the retractable tube D1 can be retracted, allowing the load to be rapidly lowered. However, when the load is lowered rapidly, an impact, accidental damage or personal injury may occur. Therefore, this prior art design is still not safe in use. An improvement in this regard is desired.